Added summarized notes.txt

connection.txt

@@ -6,6 +6,8 @@ When connected, the field control app responds with:
 
 03 01 64 00 00 00 00 BA 00 7C 1C 88 00 00 8E 67
 
+The brain I got this packet from has an ID of 88 1c 7C 00, so it looks like bytes 8-11 of this message are the brain ID(aka serial number)
+
 Next the controller sends:
 
 13 20 00 00 1A D2 1C 00 00 00 00 00 00 00 96 F0

notes.txt

@@ -0,0 +1,29 @@
+General:
+- All messages end in a two-byte CRC-16/CCIT-FALSE
+
+Connection Sequence:
+- For some reason, the first 4 packets are 16 bytes long.
+<- Controller starts by sending a "discover" message(0x0A) every 20ms
+  - Unsure what any of the fields in this packet mean, likely that a multi-byte identifier for the controller is included somewhere, and flags
+-> When FC is powered on, it responds to the 0x0A with a 0x03
+  - For 0x03 the first two bytes seem to be flags, and bytes 8-11 are the brains 4-byte ID, byte 7 also has bits set, but unsure what they mean
+<- Controller responds to 0x03 with 0x13
+  - No idea what any of these fields mean, but sending the same seems to work
+-> FC responds with 0x02 ACK
+
+- From now on, all packets are 32 bytes long
+<- Controller sends "start something idk" packet 0x11
+  - All bits are set to zero in the packets I've seen
+-> FC responds with 0x04 with byte 2 set to 0x14
+<- Controller ACKs 0x02
+-> FC ACKs the ACK 0x02
+
+Control Sequence:
+- After this startup sequence is completed(actually just after the first 16 byte sequence is completed, not sure what the 0x11 sequence is for), the controller starts a sequence of sending 0xA7 packets every 20ms
+<- Controller sends 0xA7 with the robot name, control status flags, system status flags, and timer.
+- At this point the FC can respond in two ways:
+ 1) -> FC sends 0x02 to ACK the 0xA7, controller continues operation and sends 0xA7 again in 20ms with the same info
+ 2) -> FC sends 0x53 to update the info with control flags and timer. Controller sends 0xA7 again in 20ms and it should contain the updated info.
+- The way I handle this in the code is to have an "expected state" for the timer and control flags(control flags can be updated over serial).
+  - When receiving a 0xA7, if the info matches the "expected" send a 0x02
+  - When receiving a 0xA7, if the info does not match the "expected" send a 0x53 with the expected info